Stethoscope, hearing-trumpet, ear-trumpet, and like sound-conducting instruments.



0. BOLTE.

STETHOSGOPB, HEARING TRUMPET, EAR TRUMPET, AND LIKE SOUND CONDUCTINGINSTRUMENTS.

APPLICATION FILED SEPT. 18, 1911.

1,044,858. Q Patented Nov. 19, 1912.

Wiinexgas j'wmifo/r UNITED STATES "PATENT OFFICE.

O'IEIJO BOLTE, OF HAMBURG, GERMANY.

STETHOSCOPE, HEARING-TRUMPET, EAR-TRUMPET, AND LIKE SOUND-CONDUCTINGINSTRUMENTS.

To all whom it may concern:

Be it known that I, OTTO BOLTE, a citizen of Hamburg, and resident ofNo. Bismarckstrasse, Hamburg, in the Empire of Germany, have inventednew and useful Improvements in Stethoscopes, Hearing- Trumpets,Ear-Trumpets, and Like Sound Conducting Instruments, of which thefollowing is a specification.

The present invention relates to sound conducting instruments, such asstethoscopes, hearing trumpets, ear trumpets or the like and aims atrendering more efficient and serviceable instruments of the classreferred to. This is attained by improving the conductivity so thatscarcely anydiminution in the intensity of sound is noticeable.

I will now proceed to describe my invention more fully, reference beinghad to the accompanying drawings, in which by way of example, astethoscope is shown in Figure 1 in an end view, in Fig. 2 in alongitudinal section. Fig. 3 illustrates the application of my inventionto an ear trumpet.

Referring to Figs. 1 and 2 a denotes a funnel of any suitable externalshape, I) a diaphragm or membrane, 0 a tubular stem in the cavity of thefunnel a around the hole therein and (Z the sound conducting tubepassing through the funnel a. and through the tubular stem 0 containedtherein. The tubular stem 0 terminates a short distance from thediaphragm or membrane 1), so that an annular air channel f is produced.The mouth 6 of the tube (l extends through the diaphragm or membrane 6in a central hole of the latter. In the example illustrated the shell ofthe tube (Z is hollow, it is however to be understood that I may fillthe hollow shell with any suitable substance or chose a solid shell inthe first place.

In using the stethoscope, the tube (l is placed with its suitably shapedextremity h on the body to be examined or tested, whereas the ear isclosed against the tube (5 so that the diaphragm or membrane 6 fitstight against the auricula while the month end 6 of the tube enters themeat-us auditorius externus. The waves of the sound to be tested partlyreach the ear directly through the mouth end 6 of the tube d and partlythey enter the chamber 9 of the funnel a, where they encounter thediaphragm or membrane 6. In causing the diaphragm or Specification ofLetters Patent.

Application filed September 18, 1911.

Patented Nov. 19, 1912.

Serial No. 650,029.

mission can be materially enhanced by suit-' ably coating orimpregnating the diaphragm or membrane 5 and the reflecting surfaces ofthe tube (1 and funnel a.

In Fig. 3 is shown by way of example an ear trumpet, which may be formedat the end carrying the diaphragm or membrane b in conformity with theshape of the auric-' ula. In this car trumpet the action is reversetothat described with regard to the stethoscope of Figs. 1 and 2, i. e.the sound waves enter from the end holding the diaphragm or membrane 6and are transmitted partly directly through the tube (Z, which widenstoward the ear, and partly through the diaphragm or membrane 1), the airspace I of the funnel a and the annular channel 7'.

Owing to its extraordinary capacity for sound transmission my improvedhearing instrument by using a suitably long tube can be advantageouslyemployed for testing the noise of working machlnes of various kinds, ofwater and gas conduits and the like.

While I have shown in the accompanying drawings the preferred form of myinvention, it will be understood that I do not limit myself to theprecise form shown, for many of the details may be changed in form orposition without affecting the operativeness or utility of my invention,and I therefore reserve the right to make all such modifications as areincluded within the scope of the following claims, or of mechanicalequivalents to the structure set forth.

What I do claim as my invention, and desire to secure by Letters Patent,is:

1. A hearing instrument comprising a tube, a funnel at one end of saidtube and a diaphragm or membrane in the funnel for increasing the sound,the tube extending through the funnel and through the diaphragm ormembrane in a central hole of the latter, substantially as and for thepurposes set forth.

2. A hearing instrument comprising a tube, a funnel at one endof saidtube and a diaphragm or membrane in the funnel for increasing the sound,the tube extending through the funnel and through the diaphragm ormembrane in a central hole of the latter and widening toward thetransmission end, substantially as and for the purposes set forth.

3. In a hearing instrument comprising a tube, a funnel at one end ofsaid tube and a diaphragm or membrane in the funnel for increasing thesound, the tube extending through the funnel and through the diaphragmor membrane in a central hole of the latter, a tubular stem in thecavity of the funnel around the hole therein, said stem encircling thesound transmission tube and terminating a short distance from thediaphragm or membrane, substantially as and for the purposes set forth.

5. A hearing instrument comprising a tube, a funnel at one end of saidtube and a diaphragm or membrane in the funnel for increasing the sound,the tube extending through the funnel and through the diaphragm ormembrane in a central hole of Gopies of this patent may be obtained forphragm or membrane in a central hole of the latter having a hollowshell, filled with sound transmitting substance substantially as and forthe purposes set forth.

6. A hearing instrument comprising a tube, a funnel at one end of saidtube and a diaphragm or membrane in the funnel for increasing the sound,the tube extending through the funnel and through the diaphragm ormembrane in a central hole of the latter, leaving an annular air channelopen at the converging end of the funnel, substantially as and for thepurposes set forth.

In witness whereof I have hereunto signed my name this 4th day of Sept.1911, in the presence of two subscribing witnesses.

OTTO BOLTE.

lVitnesses ERNEST H. L. MUMMnm-Iorr', IDA CHRIST. HAFERMAN.

five cents each, by addressing the Commissioner of Patents, Washington,I). C.

